I'm trying to inherit value from previous row (based on correct subscription_id + checking for IS NULL subscription_status), but something goes wrong and I get incorrect value.
Take a look at screenshot.
If I'm not mistaken it also called last non-null puzzle, but examples of possible solution for other DB provide window function with IGNORE NULLS.
But, I'm using MySQL 8.x and it doesn't support this function.
I'm sorry, but SQL fiddle doesn't provide correct text-value for variables in my code :(
https://www.db-fiddle.com/f/wHanqoSCHKJHus5u6BU4DB/4
Or, you can see mistakes here:
SET #history_subscription_status = NULL;
SET #history_subscription_id = 0;
SELECT
c.date,
c.user_id,
c.subscription_id,
sd.subscription_status,
(#history_subscription_id := c.subscription_id) as 'historical_sub_id',
(#history_subscription_status := CASE
WHEN #history_subscription_id = c.subscription_id AND sd.subscription_status IS NULL
THEN #history_subscription_status
ELSE
sd.subscription_status
END
) as 'historical'
FROM
calendar c
LEFT JOIN
subscription_data sd ON sd.date = c.date AND sd.user_id = c.user_id AND sd.subscription_id = c.subscription_id
ORDER BY
c.user_id,
c.subscription_id,
c.date
I expect to get results for this query in this way:
IMPORTANT: I'm going to use this code for a lot of data (about 1 mln rows), so it very important for me to avoid additional select or subquery that can slow down the execution of the query.
Related
So i'm trying to select unread messages with a query, but the results are blank. I need to get the info from a seperate table read so it will know it was read or not. Im trying to do something like a IF statement so if readed not exists it will be unread, but i can't get it fixed
this is my query:
SELECT * FROM notify
INNER JOIN readed ON readed.acc_ID = '26' AND readed.user_ID = '6'
AND readed.msg_ID = notify.ID AND readed.readed != '1' OR readed.ID IS NULL
WHERE notify.groep = '1'
DB - readed
ID - int
user_ID - int
acc_ID - int
msg_ID - int
readed - enum ('0','1')
DB - notify
ID - int
notfi - text
thumb_src - text
title - text
url - text
groep - int
I hope someone know whats the problem!
The query seems correct to me, except the part with the OR, so I suppose that the problem is with the data. I will first try to show how you could improve the query nevertheless, and then try to show how to debug your data.
First, let's leave away the OR condition since this won't work as expected in a JOIN ON clause.
Second, when comparing integer fields to values, you should not put quotes around the values. This will only worry every person who tries to understand the query because the quotes denote string values, and it will worry (i.e. slow down) MySQL's parser, because it must convert the string values to numbers.
Third, mixing up normal WHERE conditions and JOIN ON conditions is worrying and bad style (IMHO). I always recommend to put only the conditions which actually link the tables into the JOIN ON clause, and other conditions elsewhere.
Following this advice would lead to something like that:
SELECT * FROM
notify INNER JOIN readed ON
readed.msg_ID = notify.ID
WHERE
readed.acc_ID = 26 AND
readed.user_ID = 6 AND
readed.readed != '1' AND
notify.groep = 1
This should do the same as your original query minus the OR part.
Now, since we suspect that there is a problem with the data, we can begin to debug the data. First, leave away the WHERE clause:
SELECT * FROM
notify INNER JOIN readed ON
readed.msg_ID = notify.ID
If this returns data, then you at least know that there are rows in the readed table matching rows in the notify table. If it does not return any data, then there are no rows which fit together, and have found the root of your problem.
Provided that the above returns data, re-add the WHERE clause line by line and test after each step. For example, start with
SELECT * FROM
notify INNER JOIN readed ON
readed.msg_ID = notify.ID
WHERE
readed.acc_ID = 26 AND
and continue with
SELECT * FROM
notify INNER JOIN readed ON
readed.msg_ID = notify.ID
WHERE
readed.acc_ID = 26 AND
readed.user_ID = 6 AND
and so on, testing the query each time.
That way, you hopefully will find out where the problem is. I am convinced that the problem is with the data, not with the query.
I have a MySQL query and I need to SUM the content of a column if the content contains the number 1,
This is what I have but the TotalFails returns 0
SELECT
d.SeqNo,
d.SeqText,
h.UniqueID,
h.SeqID,
h.Room,
IF(h.Status = '1', SUM(h.Status), 0) AS TotalFails
FROM ".$SequenceNo_default." d
LEFT
JOIN ".$Hist." h ON h.SeqID = d.SeqID
WHERE d.SeqActive = 1 AND DATE(CompStamp) BETWEEN DATE( '".$_SESSION['StartDate']."') AND DATE('".$_SESSION['EndDate']."')
GROUP BY h.Room
ORDER BY h.Status ASC
Can any one see where I am going wrong?
Please note that Status is a reserved keyword so you may want to change it to something else like myStatus in the statement above.
Edit
Based upon your updated question, I would rewrite your query as follows (again, avoiding the keyword STATUS by replacing Status with myStatus):
SELECT
d.SeqNo,
d.SeqText,
h.UniqueID,
h.SeqID,
h.Room,
SUM(h.myStatus) AS TotalFails
FROM ".$SequenceNo_default." d
LEFT
JOIN ".$Hist." h ON h.SeqID = d.SeqID
WHERE d.SeqActive = 1 AND DATE(CompStamp) BETWEEN DATE( '".$_SESSION['StartDate']."') AND DATE('".$_SESSION['EndDate']."')
GROUP BY h.Room, h.myStatus
ORDER BY h.myStatus ASC
As a separate side note, this should be a prepared query, rather than including the $_SESSION variable directly into the string. $_SESSION is better than $_POST or $_GET, but for maintaining the code, this would be a good habit (for example, what if the code later changes to $_POST?).
Before anyone says, I have searched through for a suitable answer for my issue but cannot find anything specific enough so I thought I'd ask it.
Basically I am trying to select a bunch of data for a report of people who have made loan applications to a website, but there are two different types: unsecured and guarantee. I need to place an IFNULL statement in the WHERE clause so that I ONLY use that clause if a certain other field isn't null.
Here is my statement:
SELECT
la.`lms_loan_application_id`,
la.`created`,
la.`updated`,
la.`loan_amount`,
la.`loan_term`,
la.`loan_document_fee`,
la.`broker_reference`,
la.`broker_sub_reference`,
laa.`first_name`,
laa.`surname`,
laa.`dob`,
laa.`email`,
laa.`mobile_number`,
laaAd.`address_postcode`,
lag.`first_name`,
lag.`surname`,
lag.`dob`,
lag.`email`,
lag.`mobile_number`,
lagAd.`address_postcode`,
lagAd.`housing_status`
FROM
loan_application AS la
JOIN
loan_application_applicant AS laa ON la.`id` = laa.`loan_application`
LEFT JOIN
loan_application_guarantor AS lag ON la.`id` = lag.`loan_application`
JOIN
loan_application_address AS laaAd ON laaAd.`loan_application_applicant` = laa.`id`
LEFT JOIN
loan_application_address AS lagAd ON lagAd.`loan_application_guarantor` = lag.`id`
WHERE
la.`status` = 'signature_given'
AND ! IFNULL(lag.`first_name`,
lag.`status` = 'signature_given')
AND laa.`status` = 'signature_given'
AND ! IFNULL(lag.`first_name`,
lagAd.`current_address` = 1)
AND laaAd.`current_address` = 1
ORDER BY la.`updated` DESC
LIMIT 10000
As you can see, I have attempted to use the IFNULLs (although in a negated way, which I assume works?) but all I get is duplicate row results and not the result set I really want.
Basically, I need to use the where clause "lag.status = 'signature_given" and "lagAd.current_address = 1" ONLY if the lag.first_name field is NOT null (i.e. there is a guarantor name) otherwise the status won't exist, and therefore the results of unsecured loans will not show. Hope I'm explaining this well enough!
In summary, I need to show all loan information, unsecured and guaranteed, and use a negated IFNULL in order to determine when the WHERE clause is to be taken into consideration.
Any help appreciated!
Thank you in advance
Michael
From this MySQLTutorial article:
Notice that you should avoid using the IFNULL function in the WHERE clause, because it degrades the performance of the query. If you want to check if a value is NULL or not, you can use IS NULL or IS NOT NULL in the WHERE clause.
Here is a WHERE clause which implements your logic correctly using IS NULL and IS NOT NULL instead of IFNULL:
WHERE la.`status` = 'signature_given' AND
(lag.`first_name` IS NULL OR
(lag.`first_name` IS NOT NULL AND lag.`status` = 'signature_given')) AND
laa.`status` = 'signature_given' AND
(lag.`first_name` IS NULL OR
(lag.`first_name` IS NOT NULL AND lagAd.`current_address` = 1)) AND
laaAd.`current_address` = 1
I have the following query, written inside perl script:
insert into #temp_table
select distinct bv.port,bv.sip,avg(bv.bv) bv, isnull(avg(bv.book_sum),0) book_sum,
avg(bv.book_tot) book_tot,
check_null = case when bv.book_sum = null then 0 else 1 end
from table_bv bv, table_group pge, table_master sm
where pge.a_p_g = '$val'
and pge.p_c = bv.port
and bv.r = '$r'
and bv.effective_date = '$date'
and sm.sip = bv.sip
query continued -- need help below (can some one help me make this efficient, or rewriting, I am thinking its wrong)
and ((sm.s_g = 'FE')OR(sm.s_g='CH')OR(sm.s_g='FX')
OR(sm.s_g='SH')OR(sm.s_g='FD')OR(sm.s_g='EY')
OR ((sm.s_t = 'TA' OR sm.s_t='ON')))
query continued below
group by bv.port,bv.sip
query ends
explanation: some $val that contain sip with
s_g ('FE','CH','FX','SH','FD','EY') and
s_t ('TA','ON') have book_sum as null. The temp_table does not take null values,
hence I am inserting them as zero ( isnull(avg(bv.book_sum),0) ) where ever it encounters a null for the following s_g and s_m ONLY.
I have tried making the query as follows but it made my script to stop wroking:
and sm.s_g in ('FE', 'CH','FX','SH','FD','EY')
or sm.s_t in ('TA','ON')`
I know this should be a comment, but I don't have the rep. To me, it looks like it's hanging because you lost your grouping at the end. I think it should be:
and (
sm.s_g in ('FE', 'CH','FX','SH','FD','EY')
or
sm.s_t in ('TA','ON')
)
Note the parentheses. Otherwise, you're asking for all of the earlier conditions, OR that sm.s_t is one of TA or ON, which is a much larger set than you're anticipating, which may cause it to spin.
I have a search page that has multiple fields that are used to create a refined search. Every field is optional. I'm trying to start crafting my sql query so that it will work given the proper variables but I'm having trouble.
Here is the SQL query I currently have:
SELECT
indicator.indid,
indicator.indicator,
indtype.indtype,
provider.provider,
report.report,
actor.actor
FROM
actor,
indicator,
indtype,
report,
provider
WHERE
indicator.indtypeid = indtype.indtypeid
AND indicator.actorid = actor.actorid
AND indicator.reportid = report.reportid
AND report.providerid = provider.providerid
AND indicator.indicator LIKE '%$indicator%'
AND indicator.indtypeid = $indtypeid;
Whenever I provide an indicator and an indtypeid, the search works just fine. However, when I leave the indtypeid field blank, and have the variable set to * (as its default value), the query returns no results. I've tried playing with the query manually and it doesn't seem to like the * or a % sign. Basically, if only an indicator is specified and no indtypeid is specified, I want to return all indicators for all indtypeids.
I'm sure I'm missing something minor, but I would appreciate any assistance that could be provided. I may be going about this all wrong in the first place.
Try this instead:
SELECT i.indid, i.indicator, it.indtype,
p.provider, r.report, a.actor
FROM actor a
INNER JOIN indicator i ON a.actorid = i.actorid
INNER JOIN indtype it ON i.indtypeid = it.indtypeid
INNER JOIN report r ON i.reportid = r.reportid
INNER JOIN provider p ON r.providerid = p.providerid
WHERE 1 = 1
AND ($indicator IS NULL OR i.indicator LIKE '%$indicator%')
AND ($indtypeid IS NULL OR i.indtypeid = $indtypeid);
So if you pass a $indicator = NULL, then the first condition AND ($indicator IS NULL OR i.indicator LIKE '%$indicator%') will be ignored since it will resolve to True, and the same thing for the second condition.
I've removed other Where condition and replace them with JOINs, and for WHERE 1 = 1 to make the query work fine in case you pass the two variables $indicator and $indtypeid with NULL values for each, in this case it will return all results since 1 = 1 always true.